摘要
Basic oxygen furnace(BOF) slag, the solid waste produced in the steelmaking process, is reused in industry, agriculture and environmental treatment. However, as an adsorbent for wastewater, the removal effect of BOF slag on anionic pollutants needs to be improved. In this study, acid and alkali were used to modify BOF slag,and the removal efficiency and mechanism of arsenic(V) with modified BOF slag in solution were studied. The effects of the As(V) initial concentration, solution pH and reaction time on the removal efficiency were determined by batch experiments, and the removal mechanism of As(V) using modified BOF slag was studied by an adsorption kinetic model and isothermal adsorption model and the Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS) spectral analysis. The results showed that the slag modified by 15% sulfuric acid had the best removal effect on As(V), while the removal effect of As(V) by alkali-modified slag was not ideal. The removal rate of As(V) by acid-modified slag increased with the increase in the initial concentration, decreased slowly with the increase in pH and reached equilibrium in 180 min. The adsorption kinetic model and isothermal adsorption model of As(V) by acid-modified BOF slag showed that the chemical adsorption was the limiting step.The FTIR and XPS analysis results showed that the silicate and ferrite in the acid-modified slag could remove As(V)in the solution by ion exchange to form an arsenate precipitate. Therefore, modified BOF slag can be used as a potential adsorbent for large scale arsenic polluted waterbody to realize the ecological utilization of industrial solid waste.
钢渣是转炉炼钢过程中产生的固体废弃物,其在工业、农业、环保等方面已得到广泛的应用。但转炉渣作为废水吸附剂,对阴离子污染物的去除效果有待提高。因而,本研究分别采用碱和酸对转炉渣进行改性,研究改性钢渣对溶液中As(V)的吸附效果和机理,以期提高转炉渣对阴离子的吸附效率。采用的吸附批处理试验用于研究最佳吸附条件;动力学与热力学模型、傅里叶红外交换光谱(FTIR)和X射线光电子能谱(XPS)用于研究改性钢渣对As(V)的吸附机理。实验结果表明,用15%硫酸改性钢渣对砷的吸附效果最好,而碱改性渣对砷的去除效果不理想。酸改性钢渣吸附As(V)的动力学符合拟二阶动力学模型,说明该吸附为主要以化学吸附为主。等温吸附模型拟合也表明,酸改性钢渣对砷的吸附过程以化学吸附为主,并且Langmiur模型拟合度最好。通过FTIR和XPS光谱分析表明,酸改性钢渣中的硅酸盐、铁酸盐可通过与溶液中As(V)发生离子交换,生成砷酸盐沉淀,从而达到去除效果。因此,改性钢渣可作为大范围砷污染水体的潜在吸附剂,实现工业固废的生态化利用。
基金
The Central Iron&Steel Research Institute(18161550A).
